Audio Research LS-2/S-200 pre/power amplifiers

The announcement in the summer of 2024 of new products from Audio Research Corp. (ARC) was not only the company’s largest-ever simultaneous release, but also, it said, ‘a fresh start [signalling] a promising future’, and ‘a renewed commitment to inclusivity and accessibility in the world of high-fidelity sound’. With the pre/power pair here priced north of £21,000, one might take that latter claim with a pinch of salt, although with the brand’s Reference Series pitched comfortably higher [HFN Apr ’25], these things are relative.

There’s certainly been a lot of change at the Minneapolis-based high-end brand founded in 1970 by the late Bill Johnson. Acquired in 2008 by Sonus faber parent Fine Sounds, it was on the move again in 2020 to TWS Enterprises, owned by its former North American sales manager, Trent Suggs, but found itself in a process called an ‘Assignment for the Benefit of Creditors’. Amid fears for its survival, the brand was bought in 2023 for just over $1m by Valerio Cora, owner of Ontario-based speaker company Acora Acoustics.

Made in Minnesota

The parent company under which Audio Research now operates is called AR Tube Audio Corporation – not strictly accurate, as Audio Research is not a completely valve-based outfit, as we’ll see. Cora says his new acquisition and Acora Acoustics will operate independently of each other, and all Audio Research products are still built by hand at the Minnesota facility.

Above:In balanced mode, the LS-2 preamplifier is, in practice, a triode tube/transistor hybrid design

That’s the backstory, and the LS-2 hybrid valve/solid-state pre (£8298) and S-200 stereo power amp (£12,798) are joined in that tranche of new arrivals – the first under the company’s new ownership – by four more models. These are the £7298 LS-3 preamp (an all-solid-state counterpart to the LS-2); the £9798 I/70 valve integrated; the S-100 power amp, at £8998 and offering half the rated 200W output of the S-200; and the D-80 tube power amplifier, at the same price as the S-200 but with a lower 80W specification from two pairs of KT150 output tubes.

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Not so minimalist**

Something there for everyone? Just about, and there’s a definite sense of the old ARC thinking meeting modern real-world appeal. The LS-2 may be a minimalist design, being line-level only with four sets of RCA inputs and two balanced XLRs, but it has a touchscreen display panel. There’s also the option of adding features with plug-in modules, either user-installable or available pre-fitted at purchase. The MM/MC phono module, with 42/62dB gain, adds £1000 to the LS-2’s price, as does ARC’s digital module, with USB, coax and optical inputs. Neither of these were fitted to the review sample, but the modules are also compatible with the LS-3 preamplifier, and the I/55 and I/70 integrated amps.

Simplicity pervades the LS-2. Outputs are provided on unbalanced RCAs and balanced XLRs see below], and the only extra here – apart from a very functional metal-bodied remote handset [see below] – is a USB-A port designated for service access. The preamp uses one triode per channel in its gain stage, driving the RCA outs directly and the balanced XLRs via a J-FET buffer – here the LS-2 is a tube/solid-state hybrid. Using either the fascia volume control or the up/down buttons on the remote reveals the clicking relays of the unit’s resistor-ladder volume control [[see Lab Report].

That front-panel touchscreen allows the user to access balance, muting and input naming, while the colour of the display can also be changed. Kudos to the designers for not loading the preamp with loads of choices, keeping the touchscreen simple and offering the same from the remote control.

Above:The LS-2 preamp has one Sovtek 6H30 triode per channel in a ‘Class A’ gain stage with constant current cathode biasing. Balanced XLR output is buffered by a J-FET stage

ARC’s S-200 power amplifier is similarly elegant – a dual-mono design right back to twin transformers, with bridged, mirror-image output stages arranged down each side of the casework. As PM discovered [see Lab Report], the amp exceeds its rated 200W/8ohm output to a degree best described as ‘more than comfortably’, although those large front-panel power meters are rather more for show than ‘go’.

ARC attack This pre/power may be designed as a more attainable path into Audio Research ownership, but there’s no sense of this being ‘ARC-lite’ – both units are reassuringly hefty, with that no-frills styling giving them a functional ‘rack equipment’ appeal. Even when confronted with the very upmarket HFN reference system [HFN Yearbook ’25], employing the dCS Varèse stack [HFN Feb ’25] as the source and Wilson Audio’s Alexx Vfx floorstanding speakers either side of the S-200, the duo looked entirely at home, and not at all outclassed.

And with nothing much to adjust or tinker with on either the preamp or the power amplifier, this is about as ‘plug and play’ as high-end audio gets. There’s a directness to the sound, too... Playing Tchaikovsky’s ‘Valse Sentimentale’ from pianist Bruce Liu’s 2024 The Seasons [Deutsche Grammophon 4866050], the LS-2/S-200 duo delivered a light, delicate touch, with notes crisply defined, although this is hardly the most demanding of recordings.

Drive time

They worked similarly well with bass player Victor Wooten’s solo ‘Improv/Amazing Grace’ from Béla Fleck & The Flecktones’ Live Art set [Warner Bros 9362-46247-2], where he makes his bass do seemingly impossible things, playing high up in its register before slamming into a driving riff. A shame about the whoopin’ and a-hollerin’ audience, but one can’t have everything!

There was excellent attack and resonance, and superb speed as Wooten accelerated through his take on the hymn tune. So far so good, but getting the S-200’s power meters moving a bit more with the title track from Frankie Goes To Hollywood’s Welcome To The Pleasuredome [ZTT CID 101] proved a little less harmonious. Yes, the lowest bass is capable of momentarily shaking your bones via big speakers like Wilson’s Alexx Vfx, but the balance was more forward than I am used to. That ‘everything thrown at the listener all at once’ effect sets in, which might prove fatiguing in some systems. If you need a little extra illumination in your sound, however, these will do the trick.

Above:LS-2 pre [top] includes bays for optional DAC and MM/MC phono modules. By default it has four single-ended (RCA) and two balanced (XLR) inputs and a pair of RCA/XLR outputs. The S-200 [bottom] has RCA/XLR inputs and single sets of 4mm speaker cable/binding posts

Exploring further, I cued up ‘High Hopes’, from Pink Floyd’s The Division Bell [EMI CD EMD 1055], enjoying the buzzing bees and church bells of the opening, that crisp piano and the warm, well-defined vocal. However, as the track gets busier, that tendency to midband forwardness made itself felt again. Compared with ARC’s warmer, but typically refined and natural-sounding tube power amps, the S-200 can sound a little ‘obvious’.

That was also the case with the tight funk of Queen’s ‘Another One Bites The Dust’ [The Game (40th anniversary reissue); Island Records 277 175 2]. John Deacon’s bass sounded fast and clean, but the rest of the mix was a little confined, despite the distinctiveness of Freddie Mercury’s vocal and Brian May’s electric guitar.

A similar effect was noted with the dark and impassioned ‘Cam Ye O’er Frae France’, from Steeleye Span’s 1973 Parcel Of Rogues [Chrysalis download], where the threatening slashes of guitar behind Maddy Prior were so impressive that her wide-ranging vocal was rendered slightly distant.

Dawn chorus

Serving this amp combination with an exemplary recording in the form of the BBC Philharmonic rendition of Britten’s ‘Sea Interludes’ [Chandos CHAN 10658], and its keen nature rewarded the performance with an impressive bass weight that more than compensated for the strident treble of the ‘Dawn’ opening. The sense of the orchestra spread out in three dimensions before the listener was palpable, and the detail of the woodwind, brass and string instruments explicit in tone. Again, bite and leading-edge detail were at the forefront here, right down to the timpani strikes of the ‘Storm’ Interlude that hit hard.

Similarly, with the performance of Rachmaninoff’s ‘The Bells’ [Harmonia Mundi HMM902788], the Royal Philharmonic Orchestra being conducted by Vasily Petrenko, there was again that feeling of forwardness. The presentation of voice, chorus and instruments was forceful and detailed, albeit with some slight eagerness to impress as the ‘density’ of the piece built to its conclusion.

Above:Dual-mono S-200 power amp has separate L/R transformers [centre] and PSU regulation [bottom left/right] serving four pairs of Onsemi transistors in each channel’s main power amp stage [on heatsinks, far left/right]

Simply does it

With other recordings, however, this is less of a problem, as was apparent with John Scofield and Dave Holland’s Memories Of Home [ECM, 96kHz/24-bit download]. In this instance, the simple guitar and bass, combined with a typically excellent ECM recording, is less challenging, with Scofield’s guitar more or less steered to one channel and Holland in the other. Simple, yes, but also a hugely enjoyable listen with a really close-up feel, and it played brilliantly to the strengths of this new Audio Research pre/power combination.

You don’t have to stick to ‘audiophile’ recordings to hear these amplifiers at their best, either. Emmylou Harris’s ‘Born To Run’, from her 1998 Spyboy album [The Grapevine Label; GRACD 241], while hardly the purest sound you’re ever going to experience, was delivered with all the live ambience of the performance intact. There was truly excellent drive here too, the gutsy S-200 power amplifier doing a great job with this style of no-nonsense rock music.

Above:The LS-2’s remote offers control over input, balance, volume, mute, mono and display adjustment

The same holds true with Florence + The Machine’s ‘Witch Dance’ [Everybody Scream , self-released; 48kHz/24-bit download]. Florence Welch’s extraordinary voice was well showcased against a dense but still beautifully detailed backing, the tight percussion driving the track along despite the swirling backing vocals and multi-layered accompaniment. Maybe it’s just a question of catching these characterful Audio Research amps on one of their good days…

Hi-Fi News Verdict

If you’re looking for maximum impact amplifiers, with the excitement dialled up to 11, you won’t go far wrong here. The no-frills approach, flexibility of the LS-2 with those plug-in options, massive power of the S-200 and the purposeful styling will also all appeal. But there’s a nagging doubt that these amps sometimes try too hard, meaning care with partnering components may be needed to tame them a little.

Sound Quality: 84%